This article is a historical and technical overview. It contains no load data, no charge weights, and no reloading instructions – identification and history only.
A Cartridge Discussed Only in Relation to Its Successor
Most of what’s written about this cartridge is actually about a different one. Here’s what’s actually verified. 450 Adams almost never appears in casual firearms writing on its own terms – it shows up as a supporting character in articles actually built around 455 Webley, mentioned in a single introductory sentence before the piece moves on to its real subject. This article exists specifically to correct that pattern, working through a direct source-verification exercise: which commonly repeated facts about 450 Adams actually trace to primary British military and Adams company documentation, and which are casually recycled 455 Webley material applied backward onto a cartridge that deserves its own independently sourced history.
This kind of verification exercise matters precisely because the two cartridges are discussed together so constantly that the boundary between them tends to blur in casual retelling. A writer summarizing British service revolver history from memory, rather than from a source specifically about 450 Adams, will naturally reach for whatever details are most readily available – and those details are overwhelmingly about 455 Webley, simply because more has been written about it. The result is a slow, cumulative drift where facts genuinely specific to one cartridge get applied to the other, not through any deliberate misinformation, but through the ordinary mechanics of how casual online summaries get written and re-written over time.
Origins: The Adams Revolver and British Service Adoption
450 Adams was adopted for British service in November 1868, formally approved on December 21 of that year, chambered for the Adams revolver – a solid-frame, double-action design that had already built a substantial reputation in percussion form before its conversion to the new self-contained metallic cartridge. This adoption carries a documented distinction worth stating precisely: 450 Adams was Britain’s first centrefire service revolver cartridge, predating every other British service handgun round this series discusses in relation to it. The original cartridge designation was genuinely cumbersome – “Cartridge S.A. Ball Breechloading, Boxer, for Dean and Adams Converted BL Revolver Pistol Mark I” – later simplified to “Cartridge S.A. Ball Pistol Revolver Adams Mark I,” officially designated 450 Boxer Mk I.
The Adams revolver platform itself evolved through several distinct models across this period, and getting the sequence right matters for anyone researching a specific surviving example. The original conversion work adapted Robert Adams’s earlier percussion-era design – already a serious commercial rival to Colt, reputable enough to have forced Colt’s London factory to close – to accept the new breechloading cartridge via an added loading gate and bored-through cylinder. The Mark II, introduced in February 1872, was not a conversion at all but a purpose-built breechloader from the outset, featuring a two-piece frame. The Mark III followed in August 1872, distinguished specifically by a patented swivel ejector replacing the earlier fixed side-mounted ejector, and went on to become the most widely issued of the three variants, seeing documented combat service through the Anglo-Zulu War of 1879, the Second Anglo-Afghan War, and the First Boer War before the platform’s front-line retirement in 1880.
Separating Independent Facts From Recycled 455 Webley Content
This is the section that does the actual verification work this article exists to perform, and it starts with the clearest example of casually recycled content this research uncovered. A claim repeated frequently in general firearms writing holds, in some version, that 455 Webley’s cartridge case was essentially derived from or based on 450 Adams’s case – a simplified lineage claim that implies a direct case-lengthening or dimensional-modification relationship, the kind this series has documented precisely elsewhere with cartridges like 44 Special’s traceable derivation from 44 Russian. The documented reality is more specific and considerably less tidy: 450 Adams, 476 Enfield, and 455 Webley all shared a common case diameter of .476 inch, which meant firearms chambered for one of these cartridges could often accept the others without modification – a genuine, useful, and independently documented fact. What is not documented, despite frequent implication in casual summaries, is that 455 Webley’s case was directly derived from 450 Adams’s case through the kind of lengthening or shortening modification this series has traced precisely in other cartridge families. Neither 450 Adams nor 476 Enfield is documented as 455 Webley’s literal parent case – they share compatible chamber dimensions without one being a direct dimensional derivative of the other.
A second recycling pattern worth flagging directly involves service history dates. Most casual summaries present a clean succession chain – 450 Adams, replaced by 476 Enfield in 1880, replaced in turn by 455 Webley in 1887 – and stop there, implying 450 Adams’s service history ends cleanly at 1880. Specialist cartridge documentation tells a considerably more interesting, independently sourced story: a 450 Adams Mark III cartridge was formally approved in 1909, under design reference RL16433/1, specifically because reserve units, the Indian Army, and the Royal Irish Constabulary continued using Adams-pattern revolvers long after the platform’s front-line British Army retirement. This 1909 reissue – a drawn brass case loaded with a 225-grain pure lead bullet and 13 grains of black powder, manufactured by both the Royal Laboratory and Eley Brothers – represents a genuine, independently documented service continuation that the simplified succession narrative consistently drops. This is precisely the kind of fact a writer summarizing 455 Webley content and applying it backward to 450 Adams would never uncover, because it belongs to 450 Adams alone.
A third boundary worth stating explicitly: the well-known 1904 Thompson-LaGarde tests, in which a British service cartridge was rated superior to 45 Colt in stopping power – a result that influenced the eventual American adoption of 45 ACP – specifically involved 455 Webley’s Mark III “cupped” bullet loading, not 450 Adams. This distinction matters because a loosely written summary discussing “British service revolver cartridges” in general terms could easily blur this specific, well-documented result across the wrong cartridge, and this article exists specifically to prevent that kind of attribution drift.
450 Adams vs 455 Webley: The Real Dimensional and Service Differences
| Specification | 450 Adams | 455 Webley Mk I | 455 Webley Mk II |
|---|---|---|---|
| Adopted | 1868 | 1891 | 1897 |
| Case type | Rimmed, straight | Rimmed, straight | Rimmed, straight |
| Bullet diameter | 0.455 in (11.6mm) | 0.455 in (11.6mm) | 0.454 in (11.5mm) |
| Case length | 0.69 in (18mm) | 0.886 in (22.5mm) | 0.770 in (19.6mm) |
| Overall length | 1.10 in (28mm) | 1.460 in (37.1mm) | 1.230 in (31.2mm) |
| Base diameter | 0.477 in (12.1mm) | 0.478 in (12.1mm) | 0.480 in (12.2mm) |
| Rim diameter | 0.510 in (13.0mm) | 0.530 in (13.5mm) | 0.535 in (13.6mm) |
| Documented muzzle velocity | approximately 550 ft/s | approximately 650 ft/s | approximately 650 ft/s |
| Maximum pressure | Not formally SAAMI/CIP rated (black powder era) | 13,000 psi | 13,000 psi |
Dimensions given are nominal, drawn from published cartridge references. This table is for historical identification only and contains no current reloading data.
The dimensional picture is clear once the two cartridges are placed side by side rather than discussed in casual succession: 455 Webley’s case runs meaningfully longer than 450 Adams’s – even the shortened Mark II cordite-era case, at 0.770 inch, exceeds 450 Adams’s 0.69-inch case by roughly 0.08 inch, with the original black-powder Mark I case running nearly two-tenths of an inch longer still. That case-length gap, combined with the shared .476-inch body diameter discussed above, is precisely what let period Webley revolvers built for the longer cartridge safely accommodate 450 Adams ammunition as well, without the reverse being true or necessary. The velocity gap is real but modest – roughly 100 feet per second favoring 455 Webley – consistent with a genuinely evolutionary rather than revolutionary performance improvement between the two cartridges.
Why the Successor Overshadowed It So Completely
455 Webley’s dominance in popular firearms writing traces to a combination of genuinely superior documented factors, not simply better marketing or louder modern fandom. Its official service run – 1887 through the end of the Second World War – dwarfs 450 Adams’s primary 1868-to-1880 front-line term by a considerable margin, even accounting for the documented 1909 Mark III reissue extending 450 Adams’s own service life into reserve and colonial use. 455 Webley also benefited from the specific, widely cited Thompson-LaGarde test result discussed above, a documented historical moment with lasting influence on American ordnance decisions that gave the cartridge a specific, quotable claim to fame 450 Adams never had.
There is also a simpler, more structural reason worth naming directly: 455 Webley anchors a considerably larger surviving population of functioning firearms, given the Webley top-break revolver’s continued issue through two world wars, while 450 Adams-chambered Adams revolvers represent a smaller, earlier, and more thoroughly retired production run. A cartridge attached to more surviving, functioning firearms naturally accumulates more modern collector and shooter attention, more forum discussion, and more casual online summary content – which is exactly the dynamic that produces the recycling pattern this article has spent its middle sections correcting. 450 Adams did not lose a documented technical argument to 455 Webley. It lost the much simpler contest of which cartridge modern writers had more reason to research directly rather than mention in passing on the way to their actual subject.
This distinction between losing a technical argument and losing a popularity contest is worth applying as a general lesson beyond this single cartridge pair. Several cartridges covered elsewhere in this series have been dismissed, misremembered, or flattened into a footnote not because a documented engineering comparison found them lacking, but because their more famous successor simply generated more surviving written material for later writers to draw from. 450 Adams is a particularly clean example of that dynamic precisely because the underlying facts, once actually traced to their sources, hold up perfectly well on their own.
Sourcing Verified Information Today
The most reliable sources for 450 Adams’s own independent history are specialist cartridge reference works and archival British military ordnance documentation – specifically, dedicated cartridge-identification resources that track List of Changes entries, design reference numbers, and Mark-by-Mark construction differences directly, rather than general firearms encyclopedias that tend to compress this cartridge’s history into a single introductory paragraph before moving on to 455 Webley. Frank C. Barnes’s Cartridges of the World is cited repeatedly across the specialist sources consulted for this article as a foundational reference for both cartridges’ documented service dates, and specialist online cartridge-collecting resources that catalog specific Mark variants by British ordnance design reference numbers provided the clearest, most independently verifiable detail on 450 Adams’s own construction history, distinct from any 455 Webley content.
Readers researching this cartridge further should apply the same discipline this article has modeled throughout: treat any claim connecting 450 Adams’s dimensions or history directly to 455 Webley with appropriate skepticism until traced to a source discussing 450 Adams specifically, rather than a source primarily about its more famous successor with a single sentence of 450 Adams content bolted onto the introduction.
Collector Identification: What to Verify
Anyone handling a period Adams revolver or 450 Adams ammunition should work through a short verification sequence given how much casual online content conflates this cartridge with its successor.
- Distinguish Mark I, II, and III Adams revolvers by their specific documented mechanical features – the ejector type and frame construction differ meaningfully across the three variants, and casual “Adams revolver” identification without checking these details risks misdating a specific example.
- Never assume 450 Adams ammunition automatically dates to the 1868-1880 primary service window – the documented 1909 Mark III reissue means genuinely period-correct 450 Adams ammunition could trace to a considerably later manufacturing date than the revolver’s own front-line retirement date might suggest.
- Confirm whether a specific Webley-pattern revolver’s chamber dimensions accommodate 450 Adams ammunition through direct measurement or documentation rather than assuming universal cross-compatibility across all British service revolvers sharing a similar general case diameter.
- Treat any claim of a direct 450 Adams-to-455 Webley case derivation as requiring independent verification rather than accepting it as settled fact, given how frequently this specific relationship gets oversimplified in casual summaries.
Practical Notes for the Modern Collector
450 Adams ammunition and components are considerably harder to source than for most cartridges covered elsewhere in this series, reflecting the cartridge’s genuinely limited surviving firearm population compared to its longer-serving successor. General case prep essentials apply to any collector or historical shooter working with period brass, and given the black-powder-era origins and lack of a formal modern pressure specification for this cartridge, the overpressure verification discipline covered elsewhere on this site applies with particular weight – any period Adams revolver intended for live fire should be inspected by a qualified gunsmith before use, given the firearm’s age and the absence of a modern, independently verified pressure standard comparable to what governs the currently produced 455 Webley cartridge covered in this series’ next entry.
A single-stage press suits the deliberate, verification-focused approach this kind of rare period cartridge work demands, and reloaders working with formed or reclaimed brass benefit from a general guide on tuning a sizing die given how far outside standard commercial dimensions this cartridge falls.
450 Adams does not need 455 Webley’s history to be interesting. It needs its own history told accurately – Britain’s first centrefire service revolver cartridge, formally documented through three distinct Mark variants spanning more than four decades of genuine service life, independently verifiable at every step for anyone willing to look past the more famous cartridge it is usually mentioned alongside.
